Which bridal Cordelia should I use?

I think you will have to go with your experience. I would expect brave to be more consistent because 46 spd won't double well-merged glass cannons like Nino while brave bow will hit them twice anyways and wreck them because they're not designed to take two hits to their def. With 46 spd nowadays you're not doubling the fastest characters anyways - Karla, Ayra, Sumia, Shigure, Ishtar, the whole cast I examined in my spd powercreep study, even some characters who have been around longer like Cordelia and Raven. All of these units are completely busted against brave bow except maybe Ayra, whereas Cupid Arrow is probably enough only against Cordelia. Shigure and Sumia might have just enough def to survive a single hit (or possibly not), but they're definitely busted in all builds against brave bow.